Something like 2:1 Goldings:Bramling Cross is one of my favourite combinations for a bitter, particularly if you're going a bit more southern English in style. On its own BX can get a little one-dimensional, but she's great for blending.
Worth noting that Bramling Cross has been particularly variable of late, she really seems to feel the effect of the recent extreme vintages we've had. She lost almost all her fruit in the 2018 harvest, she went much more like her Goldings mother.